1. Field of the Invention
The present invention relates generally to devices and methods for mechanically protecting neurovascular structures, and in particular a neural structure located in or about the spine.
2. Description of the Related Art
Traumatic, inflammatory and degenerative conditions of the spine can lead to severe pain and loss of mobility. According to some studies, back and spine-related musculoskeletal impairment are the leading causes of reduced workplace productivity in the United States. Pain resulting from some types of spinal impairment may originate from a variety of underlying pathologies and clinical conditions. Some of the most common sources of pain are related to disc herniation and spinal stenosis.
Disc herniation occurs when some of the disc material found between the vertebrae is displaced and bulges into the spinal canal. Disc herniation often occurs as the disc material weakens with aging, but may also result from trauma, hereditary factors, or a combination of these and other factors. The resulting pain may be localized to the region of impingement or may radiate to the body regions innervated by the impinged nerve. The common surgical procedure for treating disc herniation involves removal of the herniated portion. The surgical procedure may also involve removal of most of the disc material and the placement of a bone graft to promote fusion between the two vertebrae to stabilize that portion of the spine. Surgical screws, rods and spacers may also be used to fuse the spine, either alone or in conjunction with a bone graft.
Spinal stenosis encompasses a series of conditions where a bony portion of the vertebral column is applying pressure to one or more segments of the spinal cord or the nerves that exit from the spinal cord. The pressure may give rise to pain or numbness in regions of the body innervated by those nerves. One form of spinal stenosis involves a narrowing of the bony canal which contains the nerves or nerve roots exiting the spinal column. The bony canal or foramen is formed by bony structures of two adjoining vertebrae of the spine, and may become narrow for a variety of reasons. These reasons include but are not limited to the growth of bone spurs into the foramen, reductions in the relative spacing between two vertebrae from deterioration of the vertebral discs, fractures from trauma or osteoporosis, or from breakdown of the facet joints where the vertebrae articulate with one another. Treatment of spinal stenosis frequently requires surgery to remove a portion of the vertebral bone to create more space for the nerves. This removal of bone may be combined with spine fusion or partial removal of an intervertebral disc. Other less common conditions that may cause nerve impingement include inflammatory disorders of the spine and tumors in the vertebrae.
Notwithstanding the foregoing, there remains a need for improved methods and devices for treating the spine.